The invention relates to a two-phase permanent magnet motor, as well as to a method for activating a three-phase inverter for operation of such a two-phase permanent magnet motor, according to the features specified in the preamble of claim 6.
In particular for the drive of centrifugal pumps of smaller and medium power (e.g. 20 W to 100 W), as are typically applied in heating installations as circulation pumps, it is counted as belonging to the state of the art, to apply asynchronous motors as wet-running motors. In order to operate these in an effective manner, i.e. to be able to adapt them to the actual requirement of the installation, it is further known to activate these by way of a frequency converter, so that they may be operated in a stepless manner over a wide rage of rotational speeds. Permanent magnet motors are even more favorable in this range. It is counted as belonging to the state of the art, to feed these with an electronic speed controller, in order to be able to operate these with different rotational speeds. In order here to achieve a high efficiency, three-phase motors are regularly applied, which are also fed by a three-phase speed controller.
In order to achieve a high efficiency with such a three-phase motor, it is necessary to wind the phase winding tightly around the respective stator tooth. The three-phase construction is comparatively complicated, in particular with motors with a segmented stator.
Against this background, it is the object of the invention to design a two-phase permanent magnet motor, such that on the one hand it may be operated in an energetically favorable manner, and on the other hand may be manufactured inexpensively. Furthermore, a method for activating a three-phase inverter is to be designed, such that a two-phase permanent magnet motor may be operated in an energetically favorable manner, i.e. with a high efficiency, with this method.
The part of this object with regard to the device is achieved according to the invention by a two-phase permanent magnet motor with the features specified in claim 1. The part of the object with regard to the method is achieved by the features specified in claim 6. Advantageous designs of the invention are specified in the dependent claims, the subsequent description, as well as the drawing.